In the manufacture of printed circuit boards, it is necessary to very accurately orient the board so that various work operations can be properly performed on the board. To accomplish this, printed circuit boards typically have targets at locations where the registration holes are to be drilled. These targets are manually located, and the manual location process may require partly sanding or grinding off a portion of the copper face sheet of the printed circuit board to enable the targets to be visibly identified. With the targets visibly located, the registration holes are drilled, and then the four edges of the printed circuit board are sheared so that the board forms an essentially perfect rectangle. With these preliminary work operations performed, the board can be subsequently located using the registration holes so that additional work operations can be performed.
The manual technique for target location is relatively slow and may, as indicated above, require the additional step of sanding or grinding off portions of the copper face sheet to enable the target to be visibly identified. The manual grinding, drilling and shearing operations are relatively slow and quite labor-intensive and the accuracy obtained is dependent on the skill of the workman. In addition, if the target locations on the board are outside the allowable tolerances, this manual technique has no satisfactory way of ascertaining this. Consequently, with the manual technique, the likelihood of providing registration holes at unacceptable locations is increased.